The Alkimos seawater desalination plant is expected to begin operations in mid-2028 and produce approximately 50 billion litres of drinking water per year.
As part of the Alkimos Seawater Alliance, ACCIONA has completed the construction of two undersea tunnels for the Alkimos seawater desalination plant, north of Perth, Western Australia. This milestone represents significant progress on a project valued at AUD 2.8 billion, which aims to contribute to the region’s drinking water security in the face of declining rainfall.
The two tunnels, which will house the seawater intake and discharge pipelines, extend 1.5 and 3 kilometres offshore, respectively. The longer tunnel will enable brine to be discharged at a sufficient distance from the coast to support safe dispersion and prevent impacts on marine life.
Construction of the tunnels was completed after 15 months of continuous work, during which two tunnel boring machines, named Mary and Karli, were used.
The next step will be to connect the tunnels to the intake and discharge structures, which will allow seawater to be conveyed to the plant and subsequently returned to the ocean.
A climate-independent water source
The Alkimos seawater desalination plant is expected to begin operations in mid-2028 and produce approximately 50 gigalitres of drinking water per year, equivalent to 50 billion litres.
This capacity will complement Perth’s water supply and reduce its dependence on rainfall-dependent sources and dams, helping to ensure a water source independent of weather conditions for a growing population.
Following the completion of the undersea tunnels, work will now focus on the above-ground facilities and project integration activities.
The completion of this infrastructure marks further progress on one of Western Australia’s major water projects and highlights the involvement of Spanish companies in the development of strategic infrastructure in Australia.
